Answer in brief
CVE-2026-55438 records a Medium severity (CVSS 5.8) vulnerability in Coder's workspace app CORS origin check can be bypassed via UUID-based subdomain spoofing. The current sources do not mark it as known exploited. The current feed maps coder/coder (generic), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps coder/coder (generic), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go), github.com/coder/coder/v2 (go) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| coder/codergeneric | >= 2.34.0, < 2.34.2 || >= 2.33.0, < 2.33.8 || >= 2.30.0, < 2.32.7 || < 2.29.17 | Not reported |
| github.com/coder/coder/v2go | >=2.34.0,<2.34.2 | 2.34.2 |
| github.com/coder/coder/v2go | >=2.33.0,<2.33.8 | 2.33.8 |
| github.com/coder/coder/v2go | >=2.30.0,<2.32.7 | 2.32.7 |
| github.com/coder/coder/v2go | <2.29.17 | 2.29.17 |
Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 6, 2026
Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, Coder's subdomain-based workspace app proxy allowed the same-owner CORS check to be bypassed. When a workspace-name subdomain segment parsed as a UUID, the workspace was resolved by ID without confirming the URL's username matched the real owner, while the CORS middleware trusted the unverified username in the hostname. Practical exploitation requires subdomain app routing (wildcard hostname) enabled and a victim who visits the attacker's crafted app URL while authenticated. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 validates the subdomain username against the resolved workspace's actual owner and bases the same-owner CORS decision on the authoritative owner identity. No known workarounds are available.
Quoted source text, attributed separately from HOL analysis.